Contents
Introduction
General Information
How Is Ricin Obtained?
Effects of Ricin
Detection and Treatment
Pre-exposure Treatment
Post-exposure Treatment
Examples of Ricin's Use
Ricin as a Weapon of Terror Rather than Mass Destruction
Current Regulation
Contacts
Author Contact Information

April 17, 2013

Summary

In April 2013 envelopes sent to President Obama and a U.S. Senator
tested positive for ricin, a deadly toxin derived from castor beans.
Ricin has been identified as a potential bioweapon. Ricin is extremely
toxic by ingestion, inhalation, and injection. No treatment or
prophylaxis currently exists, though research into new therapies and
vaccines against ricin exposure continues. Additionally, research to
improve ricin detection is ongoing. Although governments have
investigated ricin's potential use as a military weapon,
individuals have used ricin in small quantities. Most experts believe
that ricin would be difficult to use as a weapon of mass destruction,
but do not discount its potential as a weapon of terror. Ricin is a
select agent, and its possession, transfer, or use is regulated under
domestic and international law. This report will not be updated.

Introduction

On April 2013, envelopes sent to President Obama and a U.S. Senator
tested positive for ricin, a deadly toxin derived from castor beans.
Ricin is often mentioned as a potential bioterror weapon and has been
posed a terrorist and criminal threat. For example, CBS News reported
that the Department of Homeland Security had uncovered a credible threat
of attacks using poisons, such as ricin, in salad bars and buffets, (1)
and unknown individuals have sent letters and packages containing ricin
to federal officials. (2) This report provides general information about
ricin, identifies historical examples of its use, discusses its
potential as a bioterror weapon, and summarizes how its possession is
currently regulated.

General Information

Ricin is a potent plant toxin found in the seeds of the castor
plant (Ricinus communis). It works by blocking cell protein synthesis,
which results in cell death. This cell death can lead to organ failure
and death. (3)

How Is Ricin Obtained?

Several well-known processes describe isolation of ricin from
castor beans. Several recipes for extracting ricin from castor beans are
available on the Internet, from commercial bookstores, in patents, and
in scientific literature. The industrial production of castor oil yields
bean mash with approximately 5% ricin content. The quality of these
directions varies. Some directions would produce only crude preparations
while others would produce nearly pure ricin. (4) Even the crude
preparations have been considered deadly. (5)

Effects of Ricin

Persons exposed to ricin exhibit different symptoms depending on
the route of exposure. Ingestion of ricin causes nausea, vomiting,
diarrhea, gastric hemorrhaging, and shock. With a sufficient dose, death
occurs within three to five days. Injection of ricin produces severe
internal bleeding and tissue death, which can result in the collapse of
major organ systems. Death often follows such a collapse. Inhalation of
ricin irritates the lung linings and airways, leading to weakness and
fever. Lesions may occur in the lungs causing tissue swelling, further
damage, and possibly death. (6)

The lethal dosage of ricin depends on the route of exposure.
Inhaled or injected doses as low as 3 to 5 micrograms per kilogram body
weight may be lethal. (7) This dose equals approximately 240 to 400
micrograms for a 175-pound individual. (8) The lethal dosage for
ingestion is higher because the gastrointestinal tract absorbs ricin
less effectively. Ricin does not poison through contact with intact
skin.

Detection and Treatment

Several currently available methods can detect the release of
ricin. Potential field detectors include automated air samplers that
could detect the release of aerosolized ricin and swab-type tests that
could signal the presence of ricin on surfaces. Highly sensitive
laboratory-based tests can be performed on samples gathered on site.
Some locations, such as postal facilities processing congressional mail,
have implemented detection systems. Generally though, such detectors are
not widely implemented in civilian settings. Health care workers
diagnosing ricin poisoning may be a leading signal of a covert ricin
attack.

Pre-exposure Treatment

No ricin vaccine is currently available for use by the general
public. The Department of Defense has investigated vaccines in animal
studies and engaged in human safety studies under Investigational New
Drug (IND) protocols. (9) Other research continues in the academic and
private sectors to develop new vaccines. (10) Additionally, animal
studies suggest that passive prophylaxis, (i.e., injecting animals with
antibodies obtained from other immunized animals), is effective against
injected and ingested ricin. (11) For inhaled ricin, the most effective
prophylaxis appears to be through vaccination. (12)

Post-exposure Treatment

No medicine has been approved specifically to treat ricin exposure.
The progressive nature of the toxin's effects requires
hospitalization and continual supportive care. In cases of ingestion,
the recommended treatment of activated charcoal limits the ricin
exposure. Stomach pumping may be considered if it can be performed
within an hour of ingestion. (13) Researchers continue to attempt to
find new, more effective treatments for ricin exposure. (14)

Examples of Ricin's Use

Ricin has been considered for use as a weapon since at least 1918,
when military programs investigated the feasibility of
bomb-dissemination of aerosolized ricin. (15) Such a weapon was
reportedly developed by the United States and the United Kingdom, but
never used. (16) Iraq reportedly attempted to weaponize ricin in the
1980s. (17)

In 1978, ricin was used to assassinate Bulgarian dissident Georgi
Markov in London. A novel, umbrella-based weapon was used to inject a
pellet containing ricin into Markov. Shortly after this episode, a
similar pellet was discovered to be the source of illness of another
Bulgarian exile, Vladimir Kostov.

Some individuals attempting to possess ricin, generally through its
manufacture in makeshift laboratories, have been arrested and
subsequently convicted of violations of the Biological Weapons
Anti-Terrorism Act (P.L. 101-298). (18) For example, in 2008, a man in
Las Vegas poisoned himself manufacturing ricin in a hotel room. He
survived the poisoning and was subsequently convicted of possession of a
biological toxin. (19) In other cases, unidentified individuals have
sent ricin to government officials. In October 2003 a letter containing
ricin addressed to the Department of Transportation was intercepted, and
in November 2003, the U.S. Secret Service reportedly intercepted an
envelope containing ricin addressed to the White House. (20) In February
2004, ricin was detected in the Dirksen Senate Office Building in the
mailroom of Senator Frist. (21)

Additionally, trace amounts of ricin were reportedly found in
various locales in Afghanistan, (22) and an insurgent group in Iraq
reportedly attempted to acquire ricin. (23)

Ricin as a Weapon of Terror Rather than Mass Destruction

Many experts believe that ricin would be difficult to use as a
weapon of mass destruction. Ricin needs to be injected, ingested, or
inhaled by the victim to injure. (24) Biological weapons experts
estimate that 8 metric tons would be required to cover a 100 [km.sup.2]
area with enough toxin to kill 50% of the people. Thus, using ricin to
cause mass casualties becomes logistically impractical even for a
well-funded terrorist organization. (25) Furthermore, some experts have
stated that the required preparatory steps to use ricin as a mass
casualty weapon also pose significant technical barriers that may
preclude such use by non-state actors. (26)

Although causing mass casualties would be difficult, many experts
agree that ricin could be a formidable weapon if used in small-scale
attacks. (27) The Centers for Disease Control and Prevention have listed
ricin as a Category B Agent because it would be moderately easy to
disseminate and result in moderate morbidity rates and low mortality
rates. (28) Although a string of attacks targeting dozens of victims at
a time may not produce mass devastation, they might instill terror in
the population, causing local economic disruption.

Current Regulation

Ricin is considered both a biological and a chemical weapon, and
internationally treaties explicitly prohibit its use. The United States
is a party to both the Biological Weapons Convention and the Chemical
Weapons Convention. The Biological Weapons Convention bans the
development, production, and stockpiling of biological agents or toxins
for non-peaceful purposes. The Chemical Weapons Convention bans the
development, production, stockpiling, transfer, and use of chemical
weapons. The United States has entered into multilateral agreements to
prevent the development of both chemical and biological weapons by other
nations and terrorist groups. (29)

Congress has enacted several statutes to prohibit the misuse of
ricin. The Antiterrorism and Effective Death Penalty Act of 1996 (P.L.
104-132) directed the Department of Health and Human Services to
establish a list of biological agents and toxins that could threaten
public health and safety, procedures for governing the transfer of those
agents, and training requirements for entities working with these
"select agents." The Department of Health and Human Services
lists ricin as a select agent (42 C.F.R. 73), and restricts possession,
transfer, and use of ricin under the Public Health Security and
Bioterrorism Preparedness Act of 2002 (P.L. 107-188). (30) The USA
PATRIOT Act (P.L. 107-56) limits ricin access to select bona fide
researchers who must undergo background investigation by the Federal
Bureau of Investigation. Also, facilities containing ricin above certain
thresholds must register with the Department of Health and Human
Services and maintain certain security measures. It is not illegal to
possess or transfer castor beans, nor castor bean plants; only the
isolated ricin is regulated. Both castor beans and castor bean plants
are openly sold within the United States, and castor bean plants grow
naturally in the southwest.

(4) The effectiveness of two well-publicized methods was examined
in Rene Pita, et al., "Extraction of Ricin by Procedures Featured
on Paramilitary Publications and Manuals Related to the Al Qaeda
Terrorist Network," Medicina Militar (Espaha), Vol. 60, 2004, pp.
172-175.

(5) In 1997, Thomas Leahy was convicted for possessing 0.7 grams of
a powder that was approximately 4 percent ricin. Department of Justice
officials stated that this was equal to 125 lethal doses of ricin. See
W. Seth Carus, Bioterrorism and Biocrimes: The Illicit Use of
Biological Agents Since 1900, (Washington, DC: Center for
Counter-proliferation Research, National Defense University) 2001, pp.
97-98.

(9) See, for example, United States Army Medical Research Institute
of Infectious Diseases, Department of Defense, "USAMRIID Begins
Clinical Trial of New Vaccine to Protect Against Ricin Toxin,"
Press Release, April 13, 2011.

(18) Examples of such cases can be found in Special Report on
Ricin, James Martin Center for Nonproliferation Studies, February 29,
2008; and in Toxic Terror: Assessing Terrorist Use of Chemical and
Biological Weapons, Jonathan B. Tucker, Ed. (Cambridge, MA: MIT Press)
2000.

(19) United States Attorney, District of Nevada, U.S. Department of
Justice, "Man Who Possessed Ricin and Unregistered Firearm
Silencers in Las Vegas Hotel Room Sentenced to 3 54 Years in
Prison," News Release, November 17, 2008.

(24) Some analysts have suggested that ricin may be converted into
a contact poison when combined with a solvent that can penetrate the
skin. Reportedly, the Minnesota Patriots Council planned to use this
delivery method. See Jonathan B. Tucker and Jason Pate, op. cit.

(29) For more information on this topic, see CRS Report RL31559,
Proliferation Control Regimes: Background and Status, coordinated by
Mary Beth Nikitin.

(30) For more information on laws and regulations related to
potential biological terrorism agents, see CRS Report RL32220,
Biological and Chemical Weapons: Criminal Sanctions and Federal
Regulations, by Michael John Garcia.

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